Yttrium

Yttrium was first identified in 1794 by the Finnish chemist Johan Gadolin, in a black mineral from a quarry at Ytterby, near Stockholm. That single quarry proved extraordinarily rich in rare-earth elements, and yttrium was the first drawn from it. It is a silvery transition metal, used in phosphors, lasers, and high-temperature superconductors. Yttrium provides the red phosphors of older colour screens and the phosphors of white LEDs, forms the strong garnet crystals used in lasers and microwave devices, and is a component of some high-temperature superconductors and heat-resistant ceramics. The mineral Gadolin studied at Ytterby was itself later renamed gadolinite in his honour, a rare case of a mineral being named after the person who first analysed it rather than the reverse.

Yttrium aluminium garnet, YAG, doped with neodymium, forms the crystal at the heart of the Nd:YAG laser, one of the most widely used solid-state lasers in industry and medicine, applied in everything from metal cutting and engraving to eye surgery and tattoo removal, so a metal identified from an obscure Swedish quarry now sits inside instruments used on operating tables around the world. Gadolin himself trained under the Swedish chemist Torbern Bergman and was one of the first scientists in his country to teach chemistry along the new Lavoisian lines, making his identification of yttrium as much a marker of a changing science as of a single new element.

Ytterby holds a unique place in chemistry: no other spot on Earth has given its name to so many elements. From the ores of this one small Swedish quarry came yttrium, terbium, erbium and ytterbium, four elements whose names are all fragments of Ytterby, and its minerals also yielded holmium, thulium, gadolinium and scandium besides. The rare earths were notoriously hard to separate, hiding within one another and being teased apart only over decades, so that the Ytterby cluster became a byword for the tangled discovery of the lanthanides. Yttrium, the first of them, carries the fullest form of the village's name, a modest Scandinavian place immortalised across the periodic table.

The Ytterby quarry itself was a modest feldspar and quartz mine, worked mainly for porcelain and glass raw material, and its geological richness in rare earths went unsuspected for decades after mining began there in the eighteenth century. The site closed to mining in the 1930s and is today marked only by a small commemorative plaque, a quiet monument to a single hillside that gave more elements to the periodic table than any other single locality on Earth, a fact that still surprises visiting chemists more than the low-key site itself suggests.